1. Field of the Invention
The present invention relates to an exhaust gas sensor having: a housing in which a sensor element which, for example, is ceramic and operates electrochemically is situated; and a stopper which seals off the housing, and through which at least one connecting cable is led out of the housing or into the housing.
2. Description of the Related Art
On the one hand, this stopper and the cooperation of the stopper with the connecting cable must meet the requirement for a high level of seal-tightness. Due to the high level of seal-tightness, the penetration of harmful, for example corrosion-inducing, liquids and gases into the interior of the exhaust gas sensor may be effectively and permanently prevented. To achieve the seal-tightness it is necessary in particular for the stopper to have sufficient elasticity. On the other hand, as a result of the high exhaust gas temperatures to which the exhaust gas sensor is exposed, only materials having an appropriately high heat resistance are suitable for the stopper.
It is already known from published German patent application document DE 10 2005 020 793 A1 to provide a stopper made of polytetrafluoroethylene, also known as PTFE, for closing off the housing of an exhaust gas sensor. It is also provided to weld insulating jackets of connecting cables in through channels of this stopper, with the aid of fluoride-containing plastic.